MARCH is the systematic approach to casualty assessment in Tactical Combat Casualty Care. It prioritizes interventions by what kills fastest. If you treat things out of order, you might save an airway on a patient who's already bled out from a femoral hemorrhage you didn't address first.
The acronym stands for Massive hemorrhage, Airway, Respiration, Circulation, and Hypothermia/Head injury. Here's each step broken down with the clinical reasoning behind the sequence.
M - Massive Hemorrhage
Hemorrhage is first because it's the number one killer. Over 90% of potentially survivable combat deaths are from hemorrhage. You address it before anything else because a patient can bleed out in minutes from a major arterial injury, and no amount of airway management matters if they're exsanguinating.
During Care Under Fire (CUF), the only hemorrhage intervention is a tourniquet. High and tight, over the uniform, applied to any life-threatening extremity hemorrhage. Speed is everything. You're not doing a blood sweep while rounds are impacting.
In Tactical Field Care (TFC), you slow down and get systematic. Full blood sweep: gloved hands checking head, neck, bilateral axillae, chest front and back, abdomen, pelvis, groin, and all four extremities. Check your gloves after each area. The most commonly missed bleeding sites are posterior torso, axillae, groin, and scalp.
For junctional hemorrhage that you can't tourniquet, you're packing with hemostatic gauze (Combat Gauze, ChitoGauze, or Celox). Pack to the deepest point of the wound, use the entire roll, and hold direct pressure for a minimum of 3 minutes. Time it. Don't lift to check early.
TXA goes in as soon as possible after wounding. 2 grams slow IV/IO push. The 3-hour restriction has been removed from current guidelines. Earlier administration provides the greatest survival benefit. Also now indicated for significant TBI.
A - Airway
Airway obstruction is the second leading cause of preventable combat death. If your casualty is talking, screaming, or cursing at you, the airway is patent. Move on.
Snoring or gurgling means partial obstruction. Silence with no chest rise means complete obstruction. In an unconscious casualty, the tongue falls back and blocks the airway.
Per TCCC Change 24-1, the TFC airway algorithm has been simplified. Head-tilt chin-lift for positioning. For unconscious casualties without traumatic airway obstruction, use the recovery position with head tilted back and chin away from the chest. For conscious casualties with facial trauma, use the Sit-Up and Lean-Forward position. Jaw thrust and supraglottic airways are no longer recommended in TFC.
NPA has been moved to the Respiration/Breathing section and is now only indicated when SpO2 drops below 90% with impaired ventilation. It is no longer a routine airway adjunct.
If positioning and suction fail, or if there's massive facial trauma, you're doing a surgical cricothyrotomy. Palpate the cricothyroid membrane between the thyroid and cricoid cartilages, vertical skin incision, horizontal membrane stab, tracheal hook, insert a cuffed 6.0 ETT, inflate, and confirm with mandatory continuous capnography.
R - Respiration
Tension pneumothorax is the third leading cause of preventable combat death. Any penetrating wound between the nipple line and the waist, front or back, could involve the thorax.
Open pneumothorax: you hear air sucking through the wound or see bubbling blood. Apply a vented chest seal (HyFin Vent or SAM Chest Seal) on exhalation, press all edges, and always check for an exit wound. Seal both holes.
If the casualty worsens after sealing (increasing respiratory distress, absent breath sounds on one side, JVD, tracheal deviation), that's tension physiology developing. Burp the seal first: lift one corner, let trapped air escape, reseal. If no improvement, needle decompression.
Needle decompression: 14-gauge, 3.25-inch catheter at the 2nd intercostal space, midclavicular line. Insert perpendicular to the chest wall, above the third rib. The neurovascular bundle runs along the inferior border of each rib, so you go above the rib below to avoid it. Advance until you get a rush of air, remove the needle, leave the catheter, secure with tape.
C - Circulation
Now you address shock. Assess: altered mental status, tachycardia (HR over 100), weak or rapid pulse, hypotension, pale/cool/clammy skin, delayed capillary refill over 2 seconds.
Field pulse check: if you can feel a radial pulse, systolic BP is roughly 80+. Femoral means roughly 70+. Carotid only means roughly 60+.
Establish vascular access: 16-18 gauge IV in the antecubital fossa, two attempts max, then go to IO. EZ-IO in the proximal tibia. For conscious patients, give 40mg lidocaine IO before flushing.
Fluid resuscitation follows permissive hypotension: target SBP of 80-90 (exception: TBI needs SBP over 90 for cerebral perfusion). Fluid preference in order: low-titer O whole blood, 1:1:1 components, plasma plus RBCs 1:1, plasma alone, crystalloid as last resort. Never normal saline. Plasma-Lyte or Lactated Ringer's.
H - Hypothermia / Head Injury
Every trauma casualty is at risk for hypothermia, which is part of the lethal triad along with acidosis and coagulopathy. Each one makes the others worse. Prevention is far easier than treatment.
Minimize exposure during assessment. Remove all wet clothing. Insulate from the ground (this is the single most critical step). Wrap in an HPMK or whatever you have. Cover the head. Chemical heat packs to axillae and groin. Warm IV fluids if possible. Shield from wind and rain. Start early. Don't wait until the patient is cold.
For head injury: AVPU for rapid assessment, GCS when time permits. Maintain SBP over 90 and SpO2 over 90%. Do not hyperventilate unless signs of herniation are present. Head up 30 degrees. Seizure prophylaxis with Keppra 1500mg IV.
Practice the protocol
The whole point of MARCH is that it's systematic and it prioritizes correctly. Under stress, you default to your training. If your training is solid, the protocol runs automatically.
We built interactive MARCH training at medeor.app with quizzes, flashcards, and step-by-step breakdowns for every phase. Free, no login, works on your phone. Train the protocol until it's second nature.